Evt is at an early stage of development and definitely could delete or corrupt all your data. Enjoy.
Evt is a web-based (and command-line) calendar, backing onto WebDAV.

Evt provides a command-line interface onto your calendar. This interface is intended to be a complement to the cal Unix command, for when you want to know what you're doing, not just what day it is.
Simply type evt to see what's happening this week:
$ evt
November
09 Cherubs (09:00)
Preschool (13:00)
Friend over (14:00)
10 Meet up with Sammy (09:00)
Afternoon tea (15:00)
11 My Birthday (all day)
Class assembly (09:00)
Sue here (09:30)
Lunch at Jo's (13:00)
Cream tea (15:00)
12*
13* Swimming (09:30)
Remembrance service (10:00)
14
15 Work (09:00)
You can Browse the code or check it out like this:
git clone git://git.code.sf.net/p/evtcalendar/code evtcalendar-code